Download or read book Molecular Bases of Axonal Growth and Pathfinding written by U. Drescher and published by Springer. This book was released on 1997-10-08 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: This CTR-Special is on one of the most exciting topics in the neurosciences, the regulation of axonal growth during development and in the injured nervous system by attraction and repulsion. How the specific wiring of billions of neuronal connections is achieved in the brain has been of interest since the days of Cajal, and even earlier. The implications of this topic extend far beyond developmental neurobiology into the fields of applied medicine, clinical neurology and related disciplines. Following the discoveries of Eph receptors and their ligands, semaphorins and netrins, the field has greatly expanded in the past 2 years and continues to grow. Much of the current fascination for some of these molecules is related to their ambiguous roles in axonal growth promotion and repulsion.

Download or read book Molecular Bases of Axonal Growth and Pathfinding written by Uwe Drescher and published by . This book was released on 1997 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Molecular Basis of Axon Growth and Nerve Pattern Formation written by Hajime Fujisawa and published by . This book was released on 1997 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Molecular Bases of Axonal Grwth and Pathfinding written by U. Drescher and published by . This book was released on 1997 with total page 469 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Axon Growth and Guidance written by Dominique Bagnard and published by Springer Science & Business Media. This book was released on 2008-12-10 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book proposes an updated view of the current knowledge of the molecular and cellular mechanisms ensuring axon growth and guidance. The introductory chapter will remind the readers of all the features of a growth cone and the mechanisms controlling its growth. From there, one enters a fabulous journey with a growth cone, a Tom Thumb story filled with molecular encounters and complex interactions leading to one of the most fantastic developmental achievements: the nervous system wiring.

Download or read book Molecular Mechanisms of Axon Guidance in the Developing Spinal Cord written by Liseth M. Parra and published by . This book was released on 2009 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: The formation of intricate neural circuits requires that nascent axons navigate the complex environment of the developing embryo and precisely determine the trajectories that would lead them to their final synaptic targets. Although many guidance cues and their receptors have been identified, the intracellular signaling cascades that control and direct axonal growth remained to be fully understood. Developing axons constantly reassess the immediate environment to distinguish between a myriad of guidance molecules that are simultaneously present along their trajectory. Exactly how the axon interpret these signals at a specific time and space are limited, thus understanding how guidance cues work in concert during axonal pathfinding is a major goal in developmental neurobiology and in the regeneration of axonal connections after injury and disease. In this dissertation we studied the pathfinding of spinal cord commissural axons to understand the molecular mechanisms underlying changes in axonal responses from attraction to repulsion during floor plate crossing at the spinal cord ventral midline. Here, we found that chemorepellent signals emanating from floor plate cells of the Slit and class 3 Semaphorin family of proteins synergize in vitro to repel precrossing commissural axons possibly through Neuropilin2 pathways. In addition, we propose that Sonic Hedgehog (Shh) plays a pivotal role in mediating commissural axon repulsive guidance during floor plate crossing. We provide evidence that Shh is a regulator of class 3 Semaphorin signals in precrossing axons and specifically show that knockdown of Shh pathway components, Patched1 (PTC1) and Smoothened (Smo) disrupted proper guidance of commissural axons during floor plate crossing. We also show that both Smo and PTC1 are expressed around the developmental stages we studied and are key determinants of this regulation. The third major finding of this dissertation is that the activation of Semaphorin3 signals by Shh might be induced through the alteration of cAMP/PKA levels via Smo dependent activation of inhibitory G alpha proteins. Together the data presented in this dissertation propose new exciting models in which axon guidance regulatory pathways can induce profound changes in axonal navigational responses by successfully integrating and interpreting signaling inputs from external and internal axon guidance systems.

Download or read book Molecular Bases of Neural Development written by Gerald M. Edelman and published by Wiley-Interscience. This book was released on 1985 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume addresses central issues in the embryological development of the nervous system, which, while similar to that of other organs and tissues, features special and intricate mechanisms of morphogenesis. It emphasizes the description of cellular interactions at the molecular level and includes some of the first fruits from applications to neurobiology of recent developments in othera areas--notable immunology, biochemistry, molecular biology, and molecular genetics.

Download or read book Mechanisms of Axon Pathfinding and Survival written by Ali Genie Fenstermaker and published by . This book was released on 2010 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of functional neuronal circuits occurs via a series of complex events including axon pathfinding and synapse formation followed by selective pruning and refining of these circuits by means of programmed cell death and axon degeneration. The precise molecular machinery that dictates these exquisite development events is not well understood. My thesis study examines the role of Wnt signaling throughout nervous system development. Wnts have recently been identified as axon guidance molecules but the signaling pathways that mediate growth cone turning have yet to be elucidated. Furthermore, is there a connection between these guidance events and subsequent developmental pruning? To study the role of Wnt signaling through these events, I employed a variety of techniques including analysis of genetically modified mice, ex utero electroporation of rat spinal cord cultures, and pharmacological and genetic manipulation of dissociated neuronal cultures. Throughout this study, we will demonstrate that indeed, Wnt signaling mediates multiple events critical for appropriate nervous system development including appropriate anterior-posterior axon guidance of both spinal cord commissural neurons and monoaminergic neurons in the brainstem. In addition, I explored the potential role for an axon guidance pathway in mediating neuron survival. Here I investigate the role of atypical PKC (aPKC) signaling in the survival of developing cortical neurons. Inhibition of aPKC resulted in rapid axon fragmentation. We posit that not only does Wnt proteins serve as guidance cues in the developing nervous system, but that these attractive cues might also serve as trophic signals to developing axons.

Download or read book Molecular Mechanisms of Axon Growth and Regeneration written by Dana Watt and published by . This book was released on 2015 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neurons are cells with unique and extremely polarized morphologies. The axon allows communication between the cell soma and the distantly located synaptic terminal and can extend up to one meter in humans. This exceptional cellular structure therefore has specialized biological processes dedicated to its growth, maintenance and regeneration. The structure that carries out axon elongation during development and regeneration is the growth cone, which features a cytoskeletal structure that is both highly dynamic yet consistent in overall organization. The growth cone coordinates a leading edge of dynamic actin with the microtubules of the growing axon, enabling directed outgrowth while maintaining the structural integrity of the axon. In the axon, microtubules are oriented uniformly with their plus-ends facing away from the cell body, providing directionality for cargo transport streams. Axonal transport is critical during growth and after the axon has reached its target to ensure proper distribution of organelles and other necessary components of the axonal biology machinery. Axon transport is especially important because the axon is capable of independently carrying out tasks ranging from protein synthesis to synaptic transmission. Therefore a thorough understanding of microtubule biology and axon transport is critical for understanding how axons grow during development and regeneration. I first investigated the role of a neuron-specific molecular motor adaptor, JIP3, in axon elongation. JIP3 had been previously demonstrated to bind both the anterograde motor kinesin-1 and the retrograde motor complex dynein/dynactin, generating cargo-specific directional transport in the axon. Furthermore, our lab had also demonstrated that JIP3 was capable of binding directly and activating dimeric kinesin heavy chain (KHC) for motility. While the function of dimeric KHC is still debated, tetrameric kinesin-1 is known as the primary anterograde motor in axons. I therefore investigated the role of JIP3 in regulating tetrameric kinesin-1 motility, and the functional significance of this interaction in axons. I used a total internal reflection fluorescence (TIRF)-based single molecule imaging assay to demonstrate that JIP3 binds to the kinesin-1 tetramer in at least a 2:1 ratio. I also used this TIRF assay to show that JIP3 binding to the cargo-adapting kinesin light chain (KLC) activated tetrameric kinesin-1 for microtubule binding, while JIP3 binding to KHC activated tetrameric kinesin-1 motility along microtubules. Furthermore, while the JIP3/KLC interaction is dispensable for axon growth and regeneration in neurons in vitro, the JIP3/KHC interaction is necessary for both these activities. This work demonstrated that a single molecule can activate tetrameric kinesin-1 for microtubule binding and motility. Furthermore, this work demonstrated that regulation of molecular motor activity supports axon growth and regeneration. I next investigated the small GTPase Ran and its role in axon elongation. Ran is best known for its canonical function as a nuclear transport protein, but it can also stabilize microtubules during mitotic spindle formation and is located in the axon. While Ran has a proposed role in regulating a retrograde injury signaling complex in adult axons, it is unknown whether Ran also regulates cytoskeletal dynamics in developing axons. I used Ran knockdown to demonstrate that Ran promotes axon elongation on growth-promoting substrates, and restricts axon elongation on growth-inhibiting substrates. This effect is at least partially mediated by microtubule dynamics, as microtubule imaging using a cell-permeable pan-tubulin marker showed decreased microtubule dynamics in Ran knockdown cells on growth-promoting substrates. Furthermore, I demonstrated that a Ran activating protein, RanBP10, is enriched in growth cones and promotes axon elongation, and that both of these phenomena are Ran-dependent. This work raises the exciting possibility that Ran controls microtubule dynamics in the growth cone, distinct from its canonical role in nucleocytoplasmic trafficking.

Download or read book Nogo written by Tadzia Jean GrandPré and published by . This book was released on 2003 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Role of the Zebrafish Unplugged Gene in Motor Axon Pathfinding written by Jing Zhang and published by . This book was released on 2001 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development and Regenerative Capacity of Descending Supraspinal Pathways in Tetrapods written by H.J. ten Donkelaar and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this treatise, current knowledge on the neurogenesis, axonal outgrowth, synaptogenesis, and regenerative capacity of descending supraspinal pathways in tetrapods is discussed. Although emphasis is on the clawed toad, Xenopus laevis, chicken embryos, opossums and rodent data, also the data available for primates including man are presented. It will be shown that 1) the outgrowth of descending supraspinal pathways is the result of a coordinated program; 2) the pattern of early descending axonal tracts is similar in all vertebrate groups; 3) the formation of descending supraspinal pathways occurs according to a developmental sequence; 4) the earliest descending supraspinal fibers arrive in a rather immature spinal cord, and 5) the regenerative capacity of descending supraspinal pathways depends on the developmental stage the particular pathways arise.

Download or read book Cellular Migration and Formation of Neuronal Connections written by and published by Academic Press. This book was released on 2013-05-06 with total page 1081 pages. Available in PDF, EPUB and Kindle. Book excerpt: The genetic, molecular, and cellular mechanisms of neural development are essential for understanding evolution and disorders of neural systems. Recent advances in genetic, molecular, and cell biological methods have generated a massive increase in new information, but there is a paucity of comprehensive and up-to-date syntheses, references, and historical perspectives on this important subject. The Comprehensive Developmental Neuroscience series is designed to fill this gap, offering the most thorough coverage of this field on the market today and addressing all aspects of how the nervous system and its components develop. Particular attention is paid to the effects of abnormal development and on new psychiatric/neurological treatments being developed based on our increased understanding of developmental mechanisms. Each volume in the series consists of review style articles that average 15-20pp and feature numerous illustrations and full references. Volume 2 offers 56 high level articles devoted mainly to Formation of Axons and Dendrites, Migration, Synaptogenesis, Developmental Sequences in the Maturation of Intrinsic and Synapse Driven Patterns. - Series offers 144 articles for 2904 full color pages addressing ways in which the nervous system and its components develop - Features leading experts in various subfields as Section Editors and article Authors - All articles peer reviewed by Section Editors to ensure accuracy, thoroughness, and scholarship - Volume 2 sections include coverage of mechanisms which regulate: the formation of axons and dendrites, cell migration, synapse formation and maintenance during development, and neural activity, from cell-intrinsic maturation to early correlated patterns of activity

Download or read book Neuronal Guidance written by Marc Tessier-Lavigne and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the development of the brain growing nerves send out neuronal processes (axons and dendrites) that connect them to other nerve cells, sensory organs, and muscle tissue. Correct targeting of these is the basis for wiring of the entire nervous system and depends on attractive and repulsive molecular cues that guide the developing neurons to the appropriate destination. Written and edited by experts in the field, this collection from Cold Spring Harbor Perspectives in Biology examines the mechanisms underlying neuronal guidance and branching and their roles in the development and function of the nervous system. The contributors examine the major guidance cues and their receptors, the intracellular signaling pathways they activate, and their function in the context of important phenomena such as laminar organization and dendrite spacing. Other chapters consider the roles of guidance cues in development of neuronal circuits dedicated to the processing of particular sensory stimuli, such as the visual and olfactory systems. In addition, they cover the roles played by guidance cues and their receptors in neuronal regeneration and human genetic disorders, revealing important clinical implications of work in this field. The book also contains chapters discussing the function of guidance molecules in other processes, such as neuronal cell body migration, axon pruning, and regulation of neuronal cell death. In addition, it explores their roles outside the nervous system for example, in development of the vasculature. This volume is thus of general interest to cell and developmental biologists, as well as all neurobiologists interested in how the nervous system develops and functions.

Download or read book Cytomechanics written by Jürgen Bereiter-Hahn and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Genetic information determines the composition of molecules comprising cytoskeletal elements, membranes and receptors. The supramolecular arrangement of these components represents a self-assembly process controlled by physicochemical and mechanical interactions. This general hypothesis demarcates the aim of studying cellular mechanics. Description and evaluation of mechanical properties of cells and their organelles, as well as of the forces exerted by them, is the scope of this book on Cytomechanics. Emphasis is laid on the role of mechanical properties in the generation of shape and cytoplasmic motion, and on the basic principles and components determining mechanical properties.

Download or read book Neural Plasticity and Memory written by Federico Bermudez-Rattoni and published by CRC Press. This book was released on 2007-04-17 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive, multidisciplinary review, Neural Plasticity and Memory: From Genes to Brain Imaging provides an in-depth, up-to-date analysis of the study of the neurobiology of memory. Leading specialists share their scientific experience in the field, covering a wide range of topics where molecular, genetic, behavioral, and brain imaging techniq

Download or read book The Journal of Cell Biology written by and published by . This book was released on 2007 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: No. 2, pt. 2 of November issue each year from v. 19 (1963)-47 (1970) and v. 55 (1972)- contain the Abstracts of papers presented at the Annual Meeting of the American Society for Cell Biology, 3d (1963)-10th (1970) and 12th (1972)-